Skagit County, WA radon potential

EPA places Skagit County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Skagit County ranks higher in radon potential than 27% of rated counties (the 27th percentile).

How Skagit County compares

Skagit County, Washington is home to about 132,736 people across 1,730.232 square miles. That works out to roughly 77 people per square mile. Within its own EPA zone, Skagit County is bigger by population than 83% of the counties that share it. Geologically, Skagit County is grouped into EPA Region 10 alongside 141 other counties that share its rock and soil setting.

What this actually means for a house in Skagit County

A Zone 3 county like Skagit County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 label describes Skagit County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

If Skagit County tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Washington's state radon program

For Skagit County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Skagit County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

Where Skagit County's figures come from

Skagit County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.